Marking a first for Hispanics, the Democratic party announced Tuesday that San Antonio Mayor Julian Castro has been chosen to deliver the keynote address at the Democratic National Convention on Sept. 4, the convention's opening night. (ASSOCIATED PRESS / Pat Sullivan, File)

CHARLOTTE, N.C. (AP) — For this summer’s Democratic National Convention, Charlotte will add thousands of police from outside departments and spend millions on training, equipment and temporary barriers. But their biggest aid in crowd control will be one they didn’t have to purchase, build or teach: The layout of the city itself.

Convention-related activities will take place in the heart of the city’s central business district, which is flat and ringed by expressways. There are no nearby neighborhoods where protesters could overflow and cause trouble if violence erupts. Unlike Tampa, which is hosting this summer’s Republican convention, there is no adjoining body of water to complicate efforts to control crowds. Simply put, the police will have the protesters surrounded in secured areas.

Still, with so many variables to manage, the police chief acknowledges he often wakes up in the middle of the night to write down things he still needs to do. The September convention is an event unlike any the city has seen, likely to draw thousands of demonstrators who range from the peaceful and politically minded to anarchists bent on disrupting the events.

“During those demonstrations, you’re going to constantly have people trying to stir things up. If they’re not making an impact, you keep moving things along. But if they start agitating people, you have to take action,” Police Chief Rodney Monroe said in an interview. “You want to treat people fairly. As long as you facilitate helping the greater number of people out there demonstrating, we want to keep them on our side. Hopefully they’ll help us identify some of the agitators.”

The city of 760,000 is spending $50 million in federal funds to buy new equipment, train officers and make other security adjustments for the convention being held from Sept. 4-6. The police force’s yearlong preparations also included sending 100 officers to help maintain order in Chicago during chaotic protests at a NATO conference in May.

For the first two days, the Time Warner Arena in the city’s downtown will be the main venue. On the last day, President Barack Obama will make his acceptance speech at the 74,000-seat outdoor Bank of America stadium where the city’s NFL team plays. While the U.S. Secret Service and Department of Homeland Security will be responsible for security inside the convention hall and stadium, Charlotte police have to maintain order for the many gatherings surrounding the convention.

Police say they don’t know how many protesters will come, but massive rallies are already in the works. Two days before the convention, a coalition of 70 groups is planning to hold peaceful protests on economic inequality and other issues under the name Wall Street South. The national Occupy movement has also issued a loose call for protesters, as have anarchist groups.

The Charlotte area is home to Bank of America Corp. one of the nation’s largest banks by assets and other Fortune 500 companies, including Duke Energy and Lowe’s. With a number of companies in the financial industry, the city has fashioned itself as a banking hub.

The city has hosted large conventions and sporting events before, but nothing on the scale of the Democratic convention. Prominent events have included an NCAA Final Four, ACC Championship football game and the National Rifle Association’s annual meeting in 2010, which drew 70,000 people over three days.

Monroe said he expects most demonstrators at the Democratic convention to be peaceful. But department leaders are prepared for the kind of disruptive protesters who have emerged in recent years.

Monroe brings crowd-control experience from previous posts. As a commander with the Washington, D.C., police department, he was responsible for coordinating security for then-President Bill Clinton’s second inauguration in 1997.

He and other department leaders have met with law enforcement commanders from St. Paul. Minn., where the GOP convention was held in 2008; and Denver, the site of the 2008 Democratic convention. They also consulted with Boston police, where the Democrats held the 2004 convention. The police chief said he speaks every day with the Secret Service and Homeland Security about the convention.

“We’ve done our best to educate ourselves in lessons of other major cities for mass protests,” Monroe said.

With the help of the federal funds, Charlotte plans to add 2,400 to 3,400 officers from outside departments to its force of more than 1,750.

Some of the money has also been used to buy about $61,000 in software to help officers identify and mitigate security threats, $303,596 for bicycles and other field equipment, $704,795 for a command center upgrade and $937,852 to lodge visiting police officers, according to documents released by Charlotte officials.

But North Carolina’s largest city has refused to release many other details, citing national security concerns, despite public records requests by The Associated Press. Tampa also received $50 million in federal funds for security. The AP filed a similar request with the Tampa Police, but was rebuffed by officials there citing homeland security concerns.

With the convention in mind, Charlotte adopted an ordinance in January allowing it to create designated areas for people to gather for large-scale events and prevent them from carrying backpacks and other items in those areas. The protests are being held in designated areas in the business district, and the crowds can be easily moved between those areas, police said.

The city’s landscape and the close proximity of the major convention venues will help security, said J. Michael Bitzer, a history professor at Catawba College.

“Everything from Time Warner Arena to Bank of America Stadium is within fairly close proximity of everything. You’re going to have so many people concentrated in such a small area of the city that that’s a good thing,” Bitzer said. “The compactness should present a fairly clear delineation of protest space. It’s not like with the Olympics now where you’re all over England. Everybody is going to be in one kind of centralized location. The smaller the space you have to protect, the more you’re going to be able to keep a close eye on a lot going on.”

But one disadvantage: the area is close to major highways.

“You’ve got major thoroughfares — I-77 and I-277 — that are so close to these venues that the question is what’s going to be the spillover effect of maybe having to close those downs?” he said.

The major political conventions had been mostly peaceful for nearly four decades following disturbances at the Democratic gathering in Chicago 1968 and the 1972 Republican convention in Miami. But things changed in 2008 when the Republicans held their convention in St. Paul, attracting thousands of protesters. Some smashed cars, punctured tires and threw bottles in a confrontation with pepper-spray wielding police. Hundreds were arrested over a few days, including dozens of journalists.

Deputy Chief Harold Medlock said the Chicago trip showed Charlotte police were on the right track with security preparations, especially related to crowd control. He declined to elaborate on what tactics police would use.

Chicago Police Superintendent Garry McCarthy said the keys to policing a big event are “having a good plan that is agile and flexible.”

“You can’t be static, standing in one spot and expecting to handle what is going on. You have to have a ton of training to give your officers an expertise in taking people out of the crowd if they are acting up and engaging in criminal behavior,” McCarthy said.

Ninety-five arrests were made during the NATO summit in May, about 50 of which were people removed from the crowd by extraction teams that included officers on horseback. He said many of those arrested were anarchists who attacked police. He said 65 of the arrestees were from outside Chicago.

“Throwing rocks and bottles and bags of urine at us is pretty aggressive behavior,” he said.

One key tactic was clustering uniformed officers at potential targets for vandalism to prevent property damage and using bicycles to make them more mobile. McCarthy also stressed using “the soft look” —officers dressed in their normal uniforms but ready to quickly change into “turtle suits,” tactical helmets and body armor, if necessary.

“The last resort is to go to the turtle suits and batons,” McCarthy said. “There’s a psychology to that. If you come out in a confrontational manner, you are going to receive confrontation in return.”